Azo dyes and process of dyeing with azo dyes which contain an N-(hydroxysulfonylphenylalkyl)pyridone coupling component

ABSTRACT

Azo dyes useful for dyeing natural or synthetic substrates have the formula ##STR1## where n is from 1 to 4, 
     q is 1 or 2, 
     L 1  is hydrogen or C 1  -C 3  -alkyl, 
     L 2  is acetyl, carbamoyl or hydroxysulfonyl, and 
     D is the radical of a diazo component.

The present invention relates to novel azo dyes of the formula I ##STR2## where n is from 1 to 4,

q is 1 or 2,

L¹ is hydrogen or C₁ -C₃ -alkyl,

L² is acetyl, carbamoyl or hydroxysulfonyl, and

D (for q=1) is a radical of the formula ##STR3## where r is 0 or 1 t is 0 or 1, R¹ is phenyl or C₁ -C₄ -alkylphenyl, R² is hydrogen or nitro, R³ and R⁴ are each independently of the other hydrogen, C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy, R⁵ is hydrogen or C₁ -C₄ -alkanoyl, Y is C₁ -C₄ -alkylene, or (for q=2) is a radical of the formula ##STR4## where X is a bridge member and rings A and B may each be substituted independently of one another, but the radicals ##STR5## are excluded as bridge members, and to their use for dyeing natural or synthetic substrates.

The novel azo dyes of the formula I can be present either in the form of the free acid or else as salts.

Metal and ammonium salts are suitable. Metal salts can in particular be lithium, sodium or potassium salts. Ammonium salts for the purposes of the present invention are salts with substituted or unsubstituted ammonium cations. Examples of substituted ammonium cations are monoalkyl-, dialkyl-, trialkyl-, tetraalkyl- or benzyltrialkyl-ammonium cations or cations derived from nitrogen-containing five- or six-membered saturated heterocycles, such as pyrrolidinium, piperidinium, morpholinium, piperazinium or N-alkylpiperazinium cations or their N-monoalkyl- or N,N-dialkyl-substituted products. Here alkyl is to be understood as meaning in general straight-chain or branched C₁ -C₂₀ -alkyl which may be substituted by hydroxyl groups and/or interrupted by 1 to 4 oxygen atoms in ether function.

The earlier patent application PCT/EP 92/00281 describes dyes of a similar structure. Furthermore, DE-A-3 316 887 describes an azo dye whose coupling component is 1-hydroxysulfonylbenzyl-3-hydroxysulfonyl-4-methyl-6-hydroxypyrid-2-one and whose diazo component is 2-hydroxysulfonyl-4-ethoxyaniline.

It is an object of the present invention to provide novel azo dyes which have 1-(hydroxysulfonylphenylalkyl)-6-hydroxypyrid-2-ones as coupling components and which have advantageous application properties.

We have found that this object is achieved by the azo dyes of the formula I defined at the beginning.

Any alkyl or alkylene appearing in the above-mentioned formula I may be either straight-chain or branched.

L¹, R³ and R⁴ are each for example methyl, ethyl propyl or isopropyl.

R³ and R⁴ may each also be for example butyl, isobutyl, sec-butyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or sec-butoxy.

R¹ is for example phenyl, 2-, 3- or 4-methylphenyl or 2-, 3- or 4-ethylphenyl.

R⁵ is for example formyl, acetyl, propionyl, butyryl or isobutyryl.

Y is for example --CH₂ --, --(CH₂)₂ --, --(CH₂)₃ --, --(CH₂)₄ --, --CH₂ CH)(CH₃)-- or --CH(CH₃)CH(CH₃)--.

The rings A may be for example monosubstituted or disubstituted by C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy.

A suitable bridge member X is for example oxygen, sulfur or a radical of the formula SO, SO₂, C₂ H₄, ##STR6## where R⁶ is in each case hydrogen or methyl and Y is in each case as defined above.

Preference is given to azo dyes of the formula I where n is 1 or 2 and L¹ is methyl.

Preference is further given to azo dyes of the formula I where L² is hydroxysulfonyl.

Emphasis must be given to azo dyes of the formula I where q is 2 and D is a radical of the formula ##STR7## where X is as defined above.

Of particular suitability are azo dyes of the formula I where X is a radical of the formula ##STR8## where Y is C₁ - or C₂ -alkylene.

Also of particular suitability are azo dyes of the formula I where X is a radical of the formula ##STR9##

Also of particular suitability are azo dyes of the formula I where n is 2.

The azo dyes of the formula I according to the invention can be obtained in a conventional manner, for example by diazotizing a diazo component of the formula III

    D(--NH.sub.2).sub.w                                        (III),

where D is as defined above and w is 1 or 2, and coupling with a pyridone of the formula IV ##STR10## where n, L¹ and L² are each as defined above. Depending on the number w of amino groups, the diazo component III and the pyridone IV are used either in equimolar proportions or in a molar ratio of 1:2.

The azo dyes of formula I according to the invention are advantageous for dyeing natural or synthetic substrates, for example wool, leather or polyamide. The dyeings obtained have good end-use fastness properties.

Furthermore, they are suitable for the ink jet process.

Embodiments of the invention will now be more particularly described by way of example.

EXAMPLE 1

36.9 g of the compound of the formula ##STR11## were stirred up with 85 ml of concentrated hydrochloric acid, 25 ml of glacial acetic acid and 1 g of an acidic wetting agent. After cooling to 0° C., 65 ml of a 23% strength by weight aqueous sodium nitrite solution were added with a little ice to obtain a clear solution, which was stirred at from 0° to 4° C. for 3.5 hours. Excess nitrous acid was then destroyed with amidosulfuric acid, and the diazonium salt solution was run into a solution obtained as follows:

78 g of the pyridone of the formula ##STR12## were dissolved in 350 ml of water at pH 7 with sodium hydroxide solution. The solution was then cooled down to 10° C.

While the diazonium salt solution was being added, the reaction mixture was further cooled and buffered with sodium hydroxide solution to a pH of from 4 to 5. After the coupling reaction had ended, the water was removed. This left 312 g of a product containing 125 g of the dye of the formula ##STR13## and 187 g of sodium chloride.

The dye gives a yellow solution in water and dyes leather, polyamide and wool in a deep fast golden yellow shade.

The same method gives the dyes listed hereinafter:

                                      TABLE 1                                      __________________________________________________________________________      ##STR14##                                                                     Ex. No.            b a               Q    Hue                                  __________________________________________________________________________     2                  1 1               SO.sub.3 H                                                                          greenish yellow                      3                  2 1               SO.sub.3 H                                                                          greenish yellow                      4                  1 2               SO.sub.3 H                                                                          greenish yellow                      5                  2 2               SO.sub.3 H                                                                          greenish yellow                      6                  2 1               CONH.sub.2                                                                          greenish yellow                      7                  2 1               COCH.sub.3                                                                          greenish yellow                      8                  2 2               CONH.sub.3                                                                          greenish yellow                      9                  2 2               COCH.sub.3                                                                          greenish yellow                      __________________________________________________________________________

                                      TABLE 2                                      __________________________________________________________________________      ##STR15##                                                                     Ex. No.                                                                             D                                  q  Hue on leather                      __________________________________________________________________________     10                                                                                   ##STR16##                         2  golden yellow                       11                                                                                   ##STR17##                         1  reddish orange                      12                                                                                   ##STR18##                         2  yellow                              13                                                                                   ##STR19##                         1  yellow                              14                                                                                   ##STR20##                         2  yellow                              15                                                                                   ##STR21##                         2  yellow                              16                                                                                   ##STR22##                         2  strongly greenish yellow            17                                                                                   ##STR23##                         2  greenish yellow                     18                                                                                   ##STR24##                         2  greenish yellow                     19                                                                                   ##STR25##                         2  greenish yellow                     20                                                                                   ##STR26##                         2  yellow                              21                                                                                   ##STR27##                         2  yellow                              22                                                                                   ##STR28##                         2  yellow                              23                                                                                   ##STR29##                         2  yellow                              24                                                                                   ##STR30##                         2                                      __________________________________________________________________________

                                      TABLE 3                                      __________________________________________________________________________      ##STR31##                                                                     Ex. no.                                                                             r  K                          Hue                                         __________________________________________________________________________     25   0                                                                                  ##STR32##                 yellow                                      26   0                                                                                  ##STR33##                 yellow                                      27   1                                                                                  ##STR34##                 yellow                                      28   1                                                                                  ##STR35##                 yellow                                      29   1                                                                                  ##STR36##                 yellow                                      30   1                                                                                  ##STR37##                 yellow                                      __________________________________________________________________________ 

We claim:
 1. Azo dyes of the formula I ##STR38## where n is from 1 to 4q is 1 or 2, L¹ is hydrogen or C₁ -C₃ -alkyl, L² is acetyl or hydroxysulfonyl, and, when q=1, D is a radical of the formula ##STR39## where r is 0 or 1, t is 0 or 1, R¹ is phenyl or C₁ -C₄ -alkylphenyl, R² is hydrogen or nitro, R³ and R⁴ are each independently of the other hydrogen, C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy, R⁵ is hydrogen or C₁ -C₄ -alkanoyl, Y is C₁ -C₄ -alkylene, or, when q=2, is a radical of the formula ##STR40## where X is a bridge member and rings A and B may each be substituted independently of one another, wherein the radicals ##STR41## are excluded as bridge members.
 2. Azo dyes as claimed in claim 1, wherein n is 1 or 2 and L¹ is methyl.
 3. Azo dyes as claimed in claim 1, wherein L₂ is hydroxysulfonyl.
 4. Azo dyes as claimed in claim 1, wherein q is 2 and D is a radical of the formula ##STR42## where X is as defined above.
 5. A process of dyeing a natural or synthetic substrate selected from the group consisting of wool, polyamide, and leather, comprising contacting said substrate with an azo dye as claimed in claim
 1. 